STEONGYLID^ OR PALISADE-WORMS. 



61 



Groups of Nematodes. — The groups or families of Nematodes 

 of importance to the agriculturist are — 



(i) The StrongylidcB or Palisade-worms, 

 (ii) The Trichotrachdidm or Whip-worms, 

 (iii) The Ascaridm or Eoimd-worms. 

 (iv) FUaridcB or Thread-worms ; and 

 (v) The AnguillulidcB or Eelworms 

 The first four groups live as parasites upon animals, the last 

 group lives upon plants. 



SlBONGYLIDiB OR PaLISADB-WORMS. 



These worms produce many complaLats in animals, 

 are elongated and spindle-shaped, the 

 anus being placed near the tip of the 

 body, and, as in all Nematodes, the 

 anus and male opening are one and 

 the same. In these Palisade - worms 

 this male opening is surrounded by a 

 curious cup -shaped bursa, which is 

 kept expanded like an umbrella by 

 stiEF ribs (fig. 19, e). The female has 

 a pointed posterior (fig. 20). 



Lung Worms of the Sheep. 



They 



-i. 



One of the most important and de- 

 structive PaUsade-worms is the Lung- 

 worm of the lamb {Eustrongylus 

 filaria), a white worm which causes 

 the disease known as "husk" or 

 "hoose." The male worm is about 

 an inch and a half to two inches in 

 length, the female quite three inches. 

 The embryos of these worms are found 

 in damp earth, and enter the lamb during May, June, and 



Fig. 19 — The Lung Worm 

 (Eustr(mgylus JUarUi). 



A, Male; b, female; c, ovum; 

 D, enlaiged extremity of ? ; e, 

 bursa of male, a, anus ; c, in- 

 testioe ; b, uterus. 



